404 Not Found

<?php
$amount = $_GET["size"];
if ($amount > 0)
{
    $amount = $amount * 1024;
    header("Content-Type: application/octet-stream");
    header("Content-Disposition: attachment; filename='random.bin'");
    header("Content-Length: " . $amount . "\r\n");

    $buffer = "";
    $bufferlen = 102400;

    while ($bufferlen-- >= 0)
    {
        $buffer .= chr(rand(0,255));
    }

    do
    {
        $len = min($amount, $bufferlen);
        echo substr($buffer, 0, $len);
        $amount -= $len;
    } while ($amount > 0);

    echo "\r\n";
}
else
{
    header("HTTP/1.0 404 Not Found");
    echo "<h1>404 Not Found</h1>";
    echo "Requested data amount " . $amount . " is invalid.";
}